Fireproofing slab



MarchZS, 1937. I c DAVIS I 2,074,463

FIREPROOFING SLAB FiledFeb. 8, 1955 2 Sheets-Sheet l ATTORNEY.

Match 23, 1937. c. F. DAVIS FIREPROOFING SLAB Filed Feb. 8, 1935 2 sheets sheet 2 'INVENTOR. 624,4 f7 fi4///J,

ATTORNEY.

Patented Mar. 23, 1937 PATENT OFFIQE FIREPROOFING SLAB Clarke F. Davis, Short Hills, N. J., assignor by mesne assignments, to American Cyanamid & i Chemical Corporation, a corporation of Delaware Application February 8, 1933, Serial No. 655,723 13 Cl aims. (or. 72-68) j The present invention relates to a precast slab for covering beams, girders, purlins, columns or the like with fireproof or semi-fireproof material.

"In building constructions of today,it frequently happens that in a finished room the beams supporting the floor above are not flush with the ceiling, that is, the beams project downwardly from the ceiling. This is particularly true in the case of poured in place floors or floors constructed of slabs or the like. r

These exposed beams are, of course, objectionable from the standpoint of appearance and also from the standpoint that they are subject to the ravages of any fire which might occur in the room. As a result of such construction, it is the common practice to cover such beams, either by enclosing the same with metal lath or the like and then covering with a finish coat of plaster, or by applying haunch and soffit slabs, or embedding same in gypsum, concrete or the like for the same purpose. The above constructions are objectionable,flrst from the standpoint that one of them at least is not completely fireproof, and second from the standpoint that the haunch and soffit slabs must be individually made, handled and erected with consequent expense, both initial and subsequent, or if the beams are embedded in plastic material, expensive form work must first be erected.

cipal object the production of a cast slab which may be standardized in various sizes, which will replace the function of the less efficient methods above described.

It is another important object of the invention to provide a covering of the above type which may be made in such lengths as to facilitate erection, in that lengths of beams may be covered in a much shorter timewith less manipulation and 40 handling costs than has been possible heretofore.

Another important object of the invention resides in a novel method and means for securing such covering slabs to beams or the like.

The slab of this invention is, of course, equally 45 applicable to beams, girders, purlins and the chords of trusses, Whether horizontal or at an angle, and also to columns arranged vertically, it being distinctly understood that the application of the invention to such constructions shall in- 50 clude circumstances where the entire structural element is exposed or where such structural element is only partially exposed, all as will be more fully set forth hereinafter.

To this end, the invention in its preferred form 55 comprises a substantially trough-shaped precast The present invention has therefore as its prinslab of U-conflguration in lateral cross-section of such size as may be slipped onto a beam, girder, purlin, truss or column to cover the same, it being preferable that the side wall or walls of the slab shall be of such a height as to abut the ceiling or wall of the room inwhich the beam is exposed, or the bottom of the floor of the above room, or a flller or haunch slab inserted between the ceiling and the present slab, or the corresponding Wall of a facing slab when erected in a column or the like.

Where such beam, girder or purlin is arranged in the corner of a room, that is, where a U-shaped slab could not be used, the invention contemplates the similar use of a slab substantially L-shaped in lateral cross-section.

In all cases, whether for beams, girders, trusses and/ or purlins arranged horizontally or at an angle thereto or in the case of vertical columns the slab may be secured to the structural element which is to be covered bymeans more fully described hereinafter.

A convenient method and means for attaching such coverings to such structural elements may include a pair of horizontally extending rods embedded within the side wall of the slab and above the bottom thereof, one rod being arranged over the other, the top rod being located nearer the inner wall of the slab than the other. Where the slab takes the form of a substantially U shaped construction, this arrangement of rods will, of course, be duplicated for the other slab wall. In some instances, however, one rod may suflice, the other being omitted.

When such a slab is erected in place to enclose or cover a structural element having a lower truss or flange, the said truss or flange of the element Will be made to contact with and seat on the inner bottom surface of the slab. Nails or spikes may then be driven through the side wall of the slab from the outside between the two rods embedded in the slab wall, the location of such nail or spike being such that the end portion thereof will ride up on or make contact with the bottom flange or truss of the structural element and at the same time it is preferable that the topand bottom surface of the nail or spike will make contact with the upper and lower rods embedded in the slab walls respectively. Such a construction tends to produce a relative vertical movement between the body of the slab itself and the structural element covered thereby. As a result, where an under ceiling beam is so treated, the top of the slab wall tightly engages the effective ceiling and/or the inner bottom surface of the slab tightly engages rangement,

the bottom of the structural element flange. Any number of these nails, spikes, or other fastening devices may be utilized to securely fasten the slab to the structural member.

In order to increase the strength of the slab itself, U-shaped reinforcing rods, straps, cords or mesh may be embedded in the walls and the bottom of the slab. In such a construction, it is preferable that the wall reinforcement pass between the two horizontal rods in the slab wall.

In order to facilitate the fitting tightly together of contiguous ends of adjacent slabs, each slab may be reversely bevelled, stepped or ship lapped at its end portions so that there is an effective overlapping of two, adjacent slabs. This makes also for more eificient alignment of adjacent slabs and assists materially in fastening the slabs securely in place due to this overlapping arrangement.

Where desirable, an indicia, such as a mark, groove, depression or the like may be made or cast in the slab either during or subsequent to its manufacture to locate an entrance point for the nails, spikes, or other fastening devices in order that when they are driven through the slab toward the web of the structural element, they will Pass between the horizontal embedded rods and properly engage the flange or truss of the structural member.

The invention further consists in the novel arcombinaticn and construction of parts more fully hereinafter described and shown in the accompanying drawings.

In the drawings Fig. 1 is a fragmentary perspective view showing the mode of application of slabs of this invention to a floor beam.

Fig. 2 is a similar view showing the covering secured to such beam.

Fig. 3 is a side view partially in section showing the details of construction and overlapping of contiguous slabs.

Fig. 4 is a view similar to Fig. 2, showing a slab applied to a structural member of the channel type.

Fig. 5 is a sectional elevation showing an L- shaped slab applied to an I beam.

Fig. 6 is a sectional plan view showing a pair of slabs applied to a vertical column.

Fig. 7 is a sectional plan view showing a slab applied to a column not entirely exposed.

Fig. 8 is a fragmentary sectional elevation showing the mode of engagement of the nail, spike or other securing device with the embedded rods and the flange of the structural member.

Referring now with particularity to the embodiments shown in the drawings, a floor, ceiling or the like is indicated at I supported in Fig. 1, by an I beam 2 having a web 3 and a lower flange 4 projecting on each side of the vertical web.

A slab is shown in Fig. 1 to consist of a precast element of gypsum or the like, either with or without an admixture such as wood chips or their equivalent, substantially U shaped in lateral cross-section. Such a slab has" the vertical side walls 5 and a bottom section 6. Embedded within each side wall 5 are a pair of rods 1 and 8. It is to be noted from an inspection of Fig. 8 that in this modification the rods 1 are located higher up in the wall 5 of the slab than the rods 8 and the rods 1 are also nearer the inner surface of the side walls 5 than the rods 8. Both pairs of rods are located above the inner surface of the bottom section 6 of the slab. It is preferable that the rods 1 and 8 extend completely longitudinally of each slab and are entirely embedded in the walls thereof during manufacture.

Where additional strength is desired in the slab itself to resist breakage in either handling or erection, particularly where such slab is made of an inherently weak cementitious material such as gypsum or the like, reinforcing rods 9 may be used. These rods are substantially U-shaped and are embedded in both the Walls 5 and bottom 6 of the slab as shown in Fig. 8. A series of such rods may be located at proper intervals as indicated in Fig. 3. These reinforcements 9 may be either rods or may take the form of straps, mesh or in fact any type of reinforcing material which is suitable for the purpose. It is preferable, of course, that this reinforcing material 9 be located between the rods 1 and 8 as shown in Fig. 8.

In securing such a slab to a beam or the like, the former is slipped on tothe latter in a Vertical direction as shown in Fig. 1 and nails or spikes I0 (Fig. 8) driven through the vertical wall 5 and between the rods 1 and 8. The rods. are so spaced with relation to each other or the proportion of the spike I'll is suchthat the top and bot tom of the spike will make contact with the top and bottom rods 1 and 8 respectively. As. shown, when the nail I 0 is driven toward the vertical Web 3 of the beam, the end thereof ll engages the top of the flange 4 of the beam and ridesv up thereon. This action causes the entire slab to be lifted by the nail by reason of the fact that it passes between the rods 7 and 8. This results in either the top of the walls 5 of the slab tightly engaging the bottom of the floor or ceiling I or the inner surface of the slab bottom 6 tightly engaging the bottom of the flange 4 of the structural member, or both. In some instances one rod, either 1 or 8 will suffice. Obviously, any number of nails or spikes i0 may be used to secure the slab in place in an efiicient manner. The complete slab covering as thus erected is shown in Fig. 2. By varying the dimensions of the nail ID, a single size of slab may be made to accommodate itself to difierent sizes of beams as it' rides, up on the flange thereof.

Where desirable, an indicia may be made on or in the slab wall as indicating a point for the reception of the nails or spikes l0 so that they will be properly located. This indicia may conveniently take the form of a groove I2 cast in the slab during its manufacture.

Due to the fact that a slab made of cementi- 1 tious material such as gypsum, particularly with an admixture of wood chips or like fillers will readily receive nails without cracking or splitting, these spikes may be readily driven through the slab wall after the slab has been erected around the beam.

In order to assist in aligning two contiguous slabs, the end of each slab may overlap that of its neighbor by a stepped arrangement, ship'lap, or

be reversely bevelled as at l3 (Figs. 1 and 3). This not only assists in desirable alignment but each succeeding slab aids in holding the preceding'slab more securely in place.

Where the structural member takes the formof a channel as it does in Fig. 4, the same procedure may be resorted to to fasten the slab to such beam, although in this case the securing means are used only on one side. While the channel member M has a flange [5 extending only on one side of its vertical web, it has been found in actual practice that this method of fastening is amply sufficient for beams of thistype.

In case the beam whether of the I or channel (iii type occurs in the corner of a room, that is, in a circumstance as shown in Fig. 5, a substantially L-shaped slab may be used. The proportions of the side wall and beam of the, slab are so designed that when erected and fastened in place, the ends of the wall and beam will tightly abut the ceiling and wall of the structure as shown.

In applying this covering material to columns where the entire column is exposed, the construction of Fig. 6 may be resorted to. This consists in the use of two slabs with their openings facing each other, erected in exactly the same manner as heretofore described except in thiscase the side walls of the two slabs actually abut each other and form a continuation thereof. I

In cases where columns are not entirely exposed, that is, where they project only partially from a wall as shown in Fig. '7, a single U-shaped slab may be used to cover the same. In this or any preceding case, if through any inequalities of either the slabwall or the ceiling floor or wall adjacent thereto, the slab wall does not completely abut or tightly abut the same, nails, spikes, wires or the like may be resorted to to assist in securing the parts together. This is shown in Fig. 7 to consist of a nail I6, toe nailed through the corner of the slab into the wall H, or a nail l6 partially embedded in the slab wall and having a point projecting outwardly therefrom. When this arrangement is forced up against the wall II, the point of the nail penetrates the same and assists in holding the parts in place. In beams of excessive depth, haunch slabs may be erected between the top of the present slab wall and the surface of the wall, ceiling or the like. Likewise, in Fig. 6, haunch slabs may be placed between the opposed walls of the facing slabs.

In all cases it is proposed to manufacture this slab in dimensions suflicient to give complete 'flreprooflng effects although this is, of course,

not essential.

It is also proposed to standardize the slab widths and heights to accommodate diiferent sizes of beams and to produce substantial uniformity in slab weight. Where the width of the slab and height need be increased for use with larger beams, the total length may be decreased so that the weight would be substantially equal.

Obviously such slabs may be sawed or cut into any desired length where a complete slab is too long. Breaking grooves arranged at suitable intervals on the slab either inside or out may be used to assist the severing operation.

The completed job constructed according to this invention may receive a coat of plaster where such is desired or other decorations such as plastic paint or the like. Due to the interlock between slabs in an overlapping joint which makes for accurate alignment, any excessive pointing up is rendered unnecessary.

While the invention has been shown and described with particular reference to several specific modifications, it is not to be limited thereto but is to be construed broadly and restricted only by the scope of the claims.

I claim:

1. A precast slab of set cementitious material having a wall at an angle to the bottom thereof, two reinforcing rods in the wall above the bottom, said rods being offset from each other, and a. locating indicia on the outside of the Wall, for

indicating a place where slab fastening means may be applied.

2. A precast slab of set cementitious material having a wall at an angle to the bottom thereof, two reinforcing rodsin the wall above the bottom, said rods being offset from each other, and a locating groove for slab fastening means on the outside of said wall and extending longitudinally thereof.

3. A precast slab of set cementitious material having a Wall at an angle to the bottom thereof, two reinforcing rods in the wall above the bottom, said rods being offset from each other, and a locating indicia on the outside of the wall, for indicating a place where slab fastening means are to be applied, said locating indicia being in a horizontal plane between said rods.

4. A precast slab of set cementitious material of substantially U-shape in lateral cross-section, two reinforcing rods embedded in each wall of the U above the bottom thereof, one rod of each pair being near one wall of the slab than the other rods.

5. A precast slab of set cementitious material of substantially U-shape in lateral cross-section, two reinforcing rods embedded in each wall of the U above the bottom thereof, one rod of each pair being nearer one wall of the slab than the other rods, one rod being above the other.

6. A precast slab of set cementitious material of substantially U-shape in lateral crosssection, a pair of reinforcing rods embedded in each wall of the U and above the bottom thereof, one rod of each pair being nearer the inner wall of the slab than the other rods, the first mentioned rods being located higher up in the slab wall than the other rods.

'7. In combination, a structural member having a web and a flange, a slab covering therefor having a portion contacting with the member flange, a wall extending upwardly in substantial parallelism and equal extent with the web, and means to secure the slab to the member flange, including a nail or the like driven through the slab wall and contacting with the top of the member flange, said slab wall having a rod embedded therein, said nail also contacting with said rod.

8. In combination, a structural member having a web and a flange, a slab covering therefor having a portion contacting with the member flange, a wall extending upwardly in substantial parallelism with the web, and means to secure the slab to the member flange, including a nail or the like driven through the slab wall and contacting with the top of the member flange, said slab wall having two rods embedded therein, said nail also contacting with each of said rods.

9. In combination, a structural member having a web and a flange, a slab covering therefor having a portion contacting with the member flange, a Wall extending upwardly in substantial parallelism with the web, and means to secure the slab to the member flange, including a nail or the like driven through the slab Wall and contacting with the top of the member flange, said slab wall having a rod embedded therein, said nail also contacting with said rod, said nail having a beveled end adapted to ride up on the member flange when driven toward its web.

10. In combination, a structural member having a web and a flange, a slab covering therefor having a portion contacting with the member flange, a wall extending upwardly in substantial parallelism with the web, two spaced apart rods embedded in said wall and extending longitudinally of said wall, a nail driven through said wall and between the rods and contacting with each one thereof, said nail also resting on the top of said member flange whereby the slab is tightly held in contact with said structural member.

11. In combination, a structural member having a web and a flange, a slab covering therefor having a portion contacting with the member flange, a wall extending upwardly in substantial parallelism with the web and means to secure the slab to the structural member, two spaced apart rods embedded in said wall and extending longitudinally thereof, one rod being located above the other, the said upper rod being located nearer the member flange than the other, said slab securing means comprising a nail driven through said wall, the top of the nail contacting with the bottom of the top rod and the bottom of the nail contacting with the top of the bottom rod, said nail also resting on the top of said member flange, whereby the slab is tightly held in contact with said structural member.

12.. In combination, a structural member having a web and a flange, a precast slab of set cementitious material erected adjacent thereto, said slab having a longitudinally embedded rod therein, and a nail penetrating said slab, and contacting with said rod and the structural member flange.

13. In combination, a structural member, a slab covering therefor having a portion underlying said member and a wall extending upwardly alongside said member, a reinforcing rod in said wall, and securing means driven through the slab wall and contacting both with the reinforcing rod and structural member.

CLARKE F. DAVIS. 

